Compression transmission collar for fastening

ABSTRACT

A compression transmission collar apparatus ( 20 ) for implantation into a bone ( 22 ) with a hole ( 28 ) having a hole wall ( 32 ) comprising an intramedullary nail ( 34 ) defining a bore ( 40 ) and a threaded fastener ( 42 ) and a compression transmission collar ( 58 ) including an exterior face ( 64 ) and a top edge ( 60 ) and a bottom edge ( 62 ) and a first end ( 70 ) intersecting the top edge ( 60 ) at an acute angle and the bottom edge ( 62 ) at an obtuse angle and a second end ( 72 ) intersecting the top edge ( 60 ) at an obtuse angle and the bottom edge ( 62 ) at an acute angle and the first end ( 70 ) partially overlapping and opposing the second end ( 72 ) to define a slit ( 74 ) such that applying a compressional load to the top edge ( 60 ) causes the first end ( 70 ) to slide relative to and along the second end ( 72 ) causing the compression transmission collar ( 58 ) to compress axially and expand radially pressing the exterior face ( 64 ) against the hole wall ( 32 ).

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. application Ser. No.12/901,728, filed Oct. 11, 2010, the entire contents of which isincorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with Government support under contract numbersW81XWHO720119 and W81XWH1120128 awarded by the Unites States ArmyMedical Research Acquisition Activity. The Government has certain rightsin this invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention generally relates to a compression transmissioncollar apparatus for fastening two members. The subject invention isspecifically applicable to a compression transmission collar apparatusthat is implantable into bone for use in treating bone factures byskeletal fixation medical procedures.

2. Description of the Prior Art

Skeletal fixation is a well known type of medical procedure for treatingbone factures. The skeletal fixation procedures known in the arttypically call for the use of fasteners to fixate, or fasten, the endsof the fractured bone to one another. Accordingly, the fasteners andother related hardware used in typical skeletal fixation procedures areanalogous to the fasteners and other related hardware used in otherapplications such as carpentry, construction, and assembly.

U.S. Patent Application Ser. No. 12/818,395 to LeCronier et al. teachesan easily implantable and stable nail-fastener apparatus for skeletalfixation including an intramedullary nail for insertion into themedullary canal of a bone. The intramedullary nail defines a threadedbore extending transverse to the intramedullary nail. A threadedfastener including a threaded portion extending transversely to theintramedullary nail threadedly engages the bore of the intramedullarynail. A compression transmission collar of annular shape having anexterior face and a top edge is provided for receiving a compressionalload from the threaded fastener and transmitting the compressional loadto the intramedullary nail. When simplified to the more general field offasteners, the bone essentially comprises a first members defining ahole having a hole wall and the intramedullary nail comprises a secondmember defining a threaded bore. A threaded fastener then is provided tothreadedly engage the bore and fixate the first member to the secondmember. Lastly, a compression transmission collar of annular shape isprovided to transmit the compressional load of the fastener to at leastone of the fastened members.

One compression transmission collar well known in the art of fastenersand related hardware is the helical lock washer. Expired U.S. Pat. No.1,655,018 to Loutrel teaches a compression spring washer for use withfasteners. The Loutrel design discloses a helical shaped washer having atop edge and a bottom edge and a first end and a second end defining aslit. The top edge is designed to contact the threaded fastener forreceiving a compressional load from the threaded fastener and the bottomedge is design to contact and transmit the compressional load to one ofthe fastened members. Finally, due to the helical shape of the Loutreldesign, the compression spring washer has an extended length and acompressed length.

A problem with the compression transmission collars known in the art,such as the helical lock washer, is that the compressional load receivedby the compression transmission collar is transmitted axially to thesurface of the fastened member surrounding the hole or the bore. Axialtransmission of the compressional load in close proximity to the hole orbore is particularly problematic where at least one of the fastenedmembers is a brittle or easily deformable material. In such cases, theaxial transmission of the compressional load can easily cause thematerial to break, crack, or deform because it has already been weakenedby the presence of the hole or bore. This problem is especiallysignificant in skeletal fixation procedures because they involve therepair of an already fractured bone which is a brittle material.Accordingly, there remains a need for a compression transmission collarthat provides for the fastening of two members but does not transmit acompressional load to one of the fastened members in the axialdirection.

SUMMARY OF THE INVENTION

The subject invention provides for a compression transmission collarincluding an exterior face having an exterior diameter providing atleast partial insertion of the compression transmission collar into thehole of the first member. The bottom edge of the compressiontransmission collar contacts the second member for transmitting thecompressional load to the second member. The first end of thecompression transmission collar intersects the top edge at an acuteangle and the bottom edge at an obtuse angle. The second end of thecompression transmission collar intersects the top edge at an obtuseangle and the bottom edge at an acute angle. Accordingly, the first endat least partially overlaps and opposes the second end to define theslit in the compression transmission collar. In response to theapplication of a compressional load to the top edge of the compressiontransmission collar, the first end slides relative to and along thesecond end causing the compression transmission collar to expandradially and compress axially between the extended length and thecompressed length. The radial expansion of the compression transmissioncollar presses the exterior face of the compression transmission collaragainst the hole wall of the first member to securely fasten the firstmember to the threaded fastener and the second member.

By providing a compression transmission collar that expands in responseto the application of a compressional load, the subject invention solvesthe problem associated with using fasteners that apply a compressionalload in the axial direction in close proximity to a hole or bore inapplications where at least one of the fastened members is of a brittleor easily deformable material. The expansion of the compressiontransmission collar allows for the fastening of the members withoutapplying a compressional load to the first member and thereby avoids therisk of breaking, cracking, or deforming the first member. Accordingly,the subject invention is particularly useful in applications where atleast the first member is of a brittle or easily deformable materialsuch as glass, ceramic, rubber, polymers, and crystalline materials.Given the brittle characteristics of bone, the subject invention isespecially useful in the field of skeletal fixation where preserving theintegrity of the fastened members is vital for successful treatment of afractured bone.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a side perspective view of the complete compressiontransmission collar apparatus implanted in the bone;

FIG. 2 is a front view of the intramedullary nail;

FIG. 2A is an enlarged perspective view taken along line 2A-2A of FIG. 2illustrating the bore of the intramedullary nail;

FIG. 3 is a side view of the threaded fastener and the compressiontransmission collar;

FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG.3 illustrating the threaded fastener and the compression transmissioncollar;

FIG. 5 is an enlarged horizontal fragmentary cross-sectional view of aportion of FIG. 1 illustrating the compression transmission collarapparatus wherein the threaded fastener is installed parallel to thebore axis;

FIG. 6 is an enlarged horizontal fragmentary cross-sectional view of aportion of FIG. 1 illustrating the compression transmission collarapparatus wherein the threaded fastener is installed at an oblique anglerelative to the bore axis;

FIG. 7A is a side view of a first embodiment of the compressiontransmission collar wherein the slit is further defined by a gap havinga gap distance equal to zero;

FIG. 7B is an end view of the compression transmission collar of FIG.7A;

FIG. 8A is a side view of a second embodiment of the compressiontransmission collar wherein the slit is further defined by a gap havinga gap distance greater then zero;

FIG. 8B is an enlarged fragmentary view of a portion of FIG. 8Aillustrating the gap of the compression transmission collar;

FIG. 9A is a side view of the threaded fastener, a portion of the secondmember, and the compression transmission collar in an axially compressedstate;

FIG. 9B is a side view of the threaded fastener, a portion of the secondmember, and the compression transmission collar in an axially extendedstate wherein the radial contraction of the compression transmissioncollar is shown;

FIG. 10A is a side view of the threaded fastener, a portion of thesecond member, and the compression transmission collar in an axiallyextended state wherein the threaded fastener is installed at an obliqueangle to the second member;

FIG. 10B is a side view of the threaded fastener, a portion of thesecond member, and the compression transmission collar in an axiallycompressed state wherein the threaded fastener is installed at anoblique angle to the second member and the radial expansion of thecompression transmission collar is shown;

FIG. 11A is a side view of the threaded fastener, a portion of thesecond member, and the compression transmission collar in an axiallyextended state wherein the threaded fastener is installed at aperpendicular angle to the second member;

FIG. 11B is a side view of the threaded fastener, a portion of thesecond member, and the compression transmission collar in an axiallycompressed state wherein the threaded fastener is installed at aperpendicular angle to the second member and the radial expansion of thecompression transmission collar is shown;

FIG. 12 is a side view of a threaded fastener including a threadedportion adjacent a compression portion being unthreaded;

FIG. 13 is a side view of a threaded fastener including a threadedportion adjacent a compression portion being threaded;

FIG. 14 is a side view of a threaded fastener including a threadedportion disposed between a compression portion being unthreaded and anunthreaded portion adjacent the end;

FIG. 15A is a side view looking transparently through the first memberand the second member showing the installation of the threaded fastenerand the compression transmission collar wherein the threaded fastener isengaging the bore of the second member and the compression transmissionmember is still in an axially extended state;

FIG. 15B is a side view looking transparently through the first memberand the second member showing the installation of the threaded fastenerand the compression transmission collar wherein the threaded fastener isapplying a compressional load to the top edge of the compressiontransmission collar and the compression transmission collar iscompressing axially and expanding radially; and

FIG. 15C is a side view looking transparently through the first memberand the second member showing the installation of the threaded fastenerand the compression transmission collar wherein the compressiontransmission collar is in an axially compressed state and has expandedradially so that the exterior face of the compression transmissioncollar is pressed against the hole wall of the first member.

DETAILED DESCRIPTION OF THE ENABLING EMBODIMENTS

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, a compression transmission collarapparatus 20 is generally shown for implantation into a bone 22 during askeletal fixation medical procedure. The bone 22 includes a medullarycanal 24 surrounded by cortex 26. The bone 22 also includes a nearcortex hole 28 and a far cortex hole 30 located in the cortex 26. Thenear cortex hole 28 has a near cortex hole diameter (O_(NC)) and a nearcortex hole wall 32. The far cortex hole 30 has a far cortex holediameter (D_(FC)). The near cortex hole 28 and the far cortex hole 30are positioned on opposing sides of the medullary canal 24 with the nearcortex hole diameter (D_(NC)) being greater than the far cortex holediameter (D_(FC)) although the present invention is not limited to thisconfiguration. It is envisioned that the compression transmission collarapparatus 20 of the present invention may be used in a configurationlacking a far cortex hole 30 altogether.

The compression transmission collar apparatus 20 further includes anintramedullary nail 34 for insertion into the medullary canal 24 of thebone 22. The intramedullary nail 34 extends between a top end 36 and abottom end 38. The intramedullary nail 34 defines a bore 40 extendingtransverse to the intramedullary nail 34 for receiving a threadedfastener 42. Accordingly, the bore 40 may extend at a right angle or anoblique angle to the intramedullary nail 34. The bore 40 is threaded andhas a bore axis (B) extending between a near opening 44 and a faropening 46 transverse to the intramedullary nail 34. The bore 40 alsohas a bore diameter (D_(BR)) including a central bore diameter (D_(CBR))equal in diameter to the far cortex hole diameter (D_(FC)). The centralbore diameter (D_(CBR)) is disposed centrally between the near opening44 and the far opening 46 of the bore 40. As shown in FIG. 2A, the borediameter (D_(BR)) increases from the central bore diameter (D_(CBR)) tothe near opening 44 and from the central bore diameter (D_(CBR)) to thefar opening 46. Accordingly, the bore 40 defined by the intramedullarynail 34 has a hyperboloid shape although a traditional cylindricallyshaped bore 40 could alternatively be used. However, as shown in FIG. 6,the hyerboloid shape of the bore 40 is advantageous because it allowsthe threaded fastener 42 to be mounted at a variety of angles inrelation to the bore axis (B). This advantage is especially importantduring skeletal fixation medical procedures because doctors often do nothave the ability or time to assure perpendicular mounting.

The threaded fastener 42 extends along a fastener axis (A) between ahead 48 and an end 50. The threaded fastener 42 further includes acompression portion 52 and a threaded portion 54 and an unthreadedportion 56 adjacent to the end 50. The compression portion 52 does notengage the threads of the bore 40 and so the compression portion 52 maybe threaded or unthreaded. The compression portion 52 has a compressionportion diameter (D_(CP)) that is smaller than or equal to the threadedportion diameter (D_(TP)). The threaded portion 54 has a threadedportion diameter (D_(TP)) that is equal the central bore diameter(D_(CBR)). Where the configuration includes a far cortex hole 30, thefar cortex hole diameter (D_(FC)) may be equal to the central borediameter (D_(CBR)) and the threaded portion diameter (D_(TP)). The useof a threaded fastener 42 including only a threaded portion 54 runningfrom the head 48 to the end 50 is also contemplated by the presentinvention. The threaded fastener 42 extends through the intramedullarynail 34 and the far cortex hole 30 so as to extend transversely to theintramedullary nail 34 for threadedly engaging the bore 40. In aconfiguration absent the far cortex hole 30, the fastener extends onlythrough the intramedullary nail 34. By threadedly engaging the bore 40,the threaded fastener 42 applies a compressional load to theintramedullary nail 34 and fixates the intramedullary nail 34 within themedullary canal 24 of the bone 22.

The compression transmission collar apparatus 20 further includes acompression transmission collar 58 of annular shape having a top edge 60and a bottom edge 62. The top edge 60 contacts the head 48 of thethreaded fastener 42 for receiving the compressional load from thethreaded fastener 42. The bottom edge 62 contacts the intramedullarynail 34 for transmitting the compressional load to the intramedullarynail 34. The compression transmission collar 58 also has an exteriorface 64 having an exterior diameter (D_(E)) and an interior face 66having an interior diameter (D_(I)). The an interior diameter (D_(I)) isgreater than the compression portion diameter (D_(CP)) of the fastener.The interior face 66 of the compression transmission collar 58 definesan interior space 68 for providing space at least partially about thethreaded fastener 42 for allowing the fastener axis (A) to be variouslydisposed relative to the interior space 68. Accordingly, the compressiontransmission collar 58 transmits the compressional load of the threadedfastener 42 to the intramedullary nail 34 during fixation.

The compression transmission collar 58 has an extended length (L_(E))and a compressed length (L_(C)). As shown in FIG. 11A, the extendedlength (L_(E)) equals the distance between the top edge 60 and thebottom edge 62 of the compression transmission collar 58 before thecompressional force has been applied or after the compressional forcehas been removed. As shown in FIG. 11B, the compressed length (L_(C))equals the final or steady state distance between the top edge 60 andthe bottom edge 62 of the compression transmission collar 58 after thecompressional force has been applied but before the compressional forcehas been removed.

The compression transmission collar 58 further includes a first end 70and a second end 72. The first end 70 intersects the top edge 60 at anacute angle and the bottom edge 62 at an obtuse angle. The second end 72intersects the top edge 60 at an obtuse angle and the bottom edge 62 atan acute angle. The first end 70 partially overlaps and opposes thesecond end 72 to define a slit 74 such that applying the compressionalload to the top edge 60 causes the first end 70 to slide relative to andalong the second end 72. Accordingly, the application of thecompressional load to the top edge 60 of the compression transmissioncollar 58 causes the compression transmission collar 58 to compressaxially between the extended length (L_(E)) and the compressed length(L_(C)). The axial compression of the compression transmission collar 58corresponds to a radial expansion of the compression transmission collar58. In other words, as the compression transmission collar 58 is axiallycompressed, the circumference of the compression transmission collar 58increases. Thus, the exterior face 64 of the compression transmissioncollar 58 is pressed against the near cortex hole wall 32 in response tothe radial expansion of the compression transmission collar 58 caused bythe application of the compressional load. The pressure exerted by theexterior face 64 of the compression transmission collar 58 against thenear cortex hole wall 32 fastens the threaded fastener 42 and theintramedullary nail 34 to the bone 22 and prevents movement of thecompression transmission collar 58 relative to the near cortex hole 28.

The compression transmission collar 58 is made of a resilient materialso that the compression transmission collar 58 expands axially andcontracts radially in response to removal of the compressional load. Theresilient material may be but is not limited to a metal, a metal alloy,a rubber, or a polymer. Obviously, other materials may be employed andtheir use is envisioned by the present invention.

As shown in FIGS. 7A and 8A, in one embodiment of the present invention,the compression transmission collar 58 extends in a helical path betweenthe first end 70 and the second end 72 when the compression transmissioncollar 58 is at the extended length (L_(E)). The present invention isnot limited to this embodiment as the use of a compression transmissioncollar 58 that does not extend in a helical path between the first end70 and the second end 72 is also envisioned. Also shown in FIGS. 7A and8A, the exterior face 64 of the compression transmission collar 58 isgenerally trapezoidal in shape. The present invention alternativelyenvisions use of a compression transmission collar 58 including anexterior face 64 having a non-trapezoidal shape.

The slit 74 in the compression transmission collar 58 is further definedby a gap 76 having a gap distance (L_(G)). The gap distance (L_(G))equals the tangential distance between the first end 70 and the secondend 72. In one embodiment of the present invention, as shown in FIG. 8A,the gap distance (L_(G)) is greater than zero when the compressiontransmission collar 58 is at the extended length (L_(E)). In thisembodiment, the first end 70 and the second end 72 close the gap 76 suchthat the gap distance (L_(G)) becomes equal to zero in response to theapplication of the compressional load to the top edge 60 of thecompression transmission collar 58. Thus, in this embodiment, the firstend 70 is spaced from the second end 72 by the gap 76 before theapplication of the compressional force and after the removal of thecompressional force. In another embodiment of the present invention, asshown in FIG. 7A, the slit 74 is further defined by a gap 76 having agap distance (L_(G)) equal to zero. In this embodiment, the first end 70and the second end 72 remain in contact with one another before, during,and after the application of the compressional load.

The present invention also includes a method of skeletal fixationwherein the intramedullary nail 34 is fastened to the bone 22. Themethod proceeds with the step of creating a bore 40 including threads inthe intramedullary nail 34 extending transverse to the intramedullarynail 34 and inserting the intramedullary nail 34 into the medullarycanal 24 of the bone 22. The method further includes the steps offorming the near cortex hole 28 in the cortex 26 of the bone 22 inradially overlapping relationship to the bore 40 of the intramedullarynail 34 and similarly forming the far cortex hole 30 in the cortex 26 ofthe bone 22 in radially overlapping relationship to the bore 40 of theintramedullary nail 34. The method also includes the steps of insertingthe compression transmission collar 58 into the near cortex hole 28 andinserting the threaded fastener 42 through the compression transmissioncollar 58 and into the bore 40 of the intramedullary nail 34. The methodadditionally includes the steps of applying torque to the head 48 of thethreaded fastener 42 for threadedly engaging and advancing the threadedfastener 42 through the bore 40 of the intramedullary nail 34 and thefar cortex hole 30 for applying compressional load to the top edge 60 ofthe compression transmission collar 58 to compress the compressiontransmission collar 58 axially between the extended length (L_(E)) andthe compressed length (L_(C)). The axial compression is accomplished bysliding the first end 70 of the compression transmission collar 58relative to and along the second end 72 of the compression transmissioncollar 58 and results in the radial expansion of the compressiontransmission collar 58 within the near cortex hole 28. The methodproceeds with the step of removing torque from the head 48 of thethreaded fastener 42 in response to compressing the compressiontransmission collar 58 to the compressed length (L_(C)). A hard stop isfelt by the operator in response to the compression transmission collar58 reaching the compressed length (L_(C)) to notify the operator toremove the torque from the head 48 of the threaded fastener 42. The hardstop feature thus helps prevent the undertightening or overtightening ofthe threaded fastener 42. This feature is especially advantageous duringskeletal fixation medical procedures where time is limited and impropertightening cannot be easily corrected later because it quickly andpositively notifies the doctor that he or she has properly installed andtightened the threaded fastener 42.

The present invention also more generally relates to fasteningstructures for use outside of a skeletal fixation medical procedure. Acompression transmission collar apparatus 20 for fastening two members78, 80 is shown generally in FIGS. 15A-C. The compression transmissioncollar apparatus 20 includes a first member 78 defining a hole 82 havinga hole wall 84 and a second member 80 defining a bore 40 that isthreaded. The compression transmission collar apparatus 20 furtherincludes a compression transmission collar 58 of annular shape and athreaded fastener 42 having a threaded portion 54 for threadedlyengaging the bore 40. The compression transmission collar 58 has a topedge 60, a bottom edge 62, and an exterior face 64. The top edge 60contacts the threaded fastener 42 for receiving a compressional loadfrom the threaded fastener 42. The compression transmission collar 58has an extended length (L_(E)) and a compressed length (L_(C)). Theextended length (L_(E)) equals the distance between the top edge 60 andthe bottom edge 62 of the compression transmission collar 58 before thecompressional force has been applied or after the compressional forcehas been removed. The compressed length (L_(C)) equals the final orsteady state distance between the top edge 60 and the bottom edge 62 ofthe compression transmission collar 58 after the compressional force hasbeen applied but before the compressional force has been removed. Thecompression transmission collar 58 further includes and a first end 70and a second end 72 defining a slit 74.

The exterior face 64 has an exterior diameter (D_(E)) providing at leastpartial insertion of the compression transmission collar 58 into thehole 82 of the first member 78. This allows the bottom edge 62 tocontact the second member 80 for transmitting the compressional load tothe second member 80. The first end 70 intersects the top edge 60 at anacute angle and the bottom edge 62 at an obtuse angle. The second end 72intersects the top edge 60 at an obtuse angle and the bottom edge 62 atan acute angle. The first end 70 at least partially overlaps and opposesthe second end 72 to define the slit 74 such that applying thecompressional load to the top edge 60 causes the first end 70 to sliderelative to and along the second end 72. Accordingly, the application ofthe compressional load to the top edge 60 of the compressiontransmission collar 58 causes the compression transmission collar 58 tocompress axially between the extended length (L_(E)) and the compressedlength (L_(C)). The axial compression of the compression transmissioncollar 58 corresponds to a radial expansion of the compressiontransmission collar 58. In other words, as the compression transmissioncollar 58 is axially compressed, the circumference of the compressiontransmission collar 58 increases. Thus, the exterior face 64 of thecompression transmission collar 58 is pressed against the hole wall 84of the first member 78 in response to the radial expansion of thecompression transmission collar 58 caused by the application of thecompressional load. The pressure exerted by the exterior face 64 of thecompression transmission collar 58 against the hole wall 84 acts tofasten the threaded fastener 42 and the second member 80 to the firstmember 78 and prevents movement of the compression transmission collar58 relative to the hole 82 in the first member 78.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings and may be practicedotherwise than as specifically described while within the scope of theappended claims.

What is claimed is:
 1. A method of skeletal fixation of anintramedullary nail to a bone including a medullary canal surrounded bycortex and a near cortex hole and a far cortex hole by a threadedfastener having a head and a threaded portion and a compressiontransmission collar of resilient material and helical shape having a topedge and a bottom edge and a first end and a second end and an extendedlength (L_(E)) and a compressed length (L_(C)) and said first endintersecting said top edge at an acute angle and said bottom edge at anobtuse angle and said second end intersecting said top edge at an obtuseangle and said bottom edge at an acute angle and said first endpartially overlapping and opposing said second end to define a slit,said method comprising the steps of; creating a bore in theintramedullary nail extending transverse to the intramedullary nailincluding threads, inserting the intramedullary nail into the medullarycanal of the bone, forming the near cortex hole in the cortex of thebone in radially overlapping relationship to the bore of theintramedullary nail, forming the far cortex hole in the cortex of thebone in radially overlapping relationship to the bore of theintramedullary nail, inserting the compression transmission collar intothe near cortex hole, inserting the threaded fastener through thecompression transmission collar and into the bore of the intramedullarynail, applying torque to the head of the threaded fastener forthreadedly engaging and advancing the threaded fastener through the boreof the intramedullary nail and the far cortex hole and applyingcompressional load to the top edge of the compression transmissioncollar compressing the compression transmission collar axially betweenthe extended length (L_(E)) and the compressed length (L_(C)) by slidingthe first end of the compression transmission collar relative to andalong the second end of the compression transmission collar andexpanding the compression transmission collar radially within the nearcortex hole in response to compressing the compression transmissioncollar axially, and removing torque from the head of the threadedfastener in response to compressing the compression transmission collarto the compressed length (L_(C)).
 2. A method of skeletal fixation of anintramedullary nail to a bone including a medullary canal surrounded bycortex and a cortex hole by a fastener having a head and a compressiontransmission collar of resilient material having a top edge and a bottomedge and a first end and a second end and an extended length (L_(E)) anda compressed length (L_(C)) and said first end intersecting said topedge at an acute angle and said bottom edge at an obtuse angle and saidsecond end intersecting said top edge at an obtuse angle and said bottomedge at an acute angle and said first end partially overlapping andopposing said second end to define a slit, said method comprising thesteps of; creating a bore in the intramedullary nail extendingtransverse to the intramedullary nail, inserting the intramedullary nailinto the medullary canal of the bone, forming the cortex hole in thecortex of the bone in radially overlapping relationship to the bore ofthe intramedullary nail, inserting the compression transmission collarinto the cortex hole, inserting the fastener through the compressiontransmission collar and into the bore of the intramedullary nail,applying torque to the head of the fastener for engaging and advancingthe fastener through the bore of the intramedullary nail and applyingcompressional load to the top edge of the compression transmissioncollar compressing the compression transmission collar axially betweenthe extended length (L_(E)) and the compressed length (L_(C)) by slidingthe first end of the compression transmission collar relative to andalong the second end of the compression transmission collar andexpanding the compression transmission collar radially within the cortexhole in response to compressing the compression transmission collaraxially, and removing torque from the head of the fastener in responseto compressing the compression transmission collar to the compressedlength (L_(C)).